Cloudflare Containers, rebuilt to scale agent sandboxes

Today, we’re making Cloudflare Containers more programmable and optimized for agent workloads. Agents don't deploy sandboxes ahead of time. They create sandboxes on demand, for each task, expect them to be ready immediately, and be able to pause and resume. So we rearchitected Containers to meet these requirements: your code can now choose each sandbox's image and instance type at runtime, Containers start 6x faster, and filesystem snapshots are available in public beta.

To make this possible, we’ve rethought the Containers infrastructure from the bottom up. A new scheduling policy moves control over each sandbox into application code, while a redesigned runtime provides a faster path to a running Container. In ComputeSDK’s independent benchmark, median startup fell from just over four seconds to 648 milliseconds, and, in our own preliminary tests, burst testing successfully created hundreds of thousands of containers in seconds.

All of this builds on what has always set Containers on Cloudflare apart: every Container gets its own Durable Object, a persistent, programmable controller running right next to it that manages its lifecycle, outbound traffic, and more. We are bringing more capabilities directly to the native ctx.container API, so the Durable Object can control its Container without a wrapper class in between, and we’re carrying this model into Sandbox SDK 1.0.

As we wrote earlier this year, your agent needs a computer. These changes make Containers a better complement to Workers, Dynamic Workers, and Durable Objects when agents need a full Linux workspace.

Rethinking Containers’ runtime for agents